Companies like Canon, Barclays and Google have not only register brand top-level domains (TLDs) but have begun using them.
Here is a running list of the new .brand domains currently live:
BNP Paribas: group.bnpparibas
Sener: www.aerospace.sener (among others)
Yandex: travel.yandex (among others, redirect currently)
Cisco uses gTLDs currently as redirects, such as cloud.cisco.
If you have a brand to add, please let me know.